Waterproof bags
Used to separate and keep various items dry in your bag. Good for keeping valuables and electronics. Simple Ziploc style bags are good for this. However, much better are the plastic bags made by 
Aloksak.
These are very strong but lightweight, transparent storage bags. They come in four sizes: 7 x 4.5 inch, 6.75 x 6 inch, 9 x 6 inch and 12 x 12 inch.
They are made of a patented, super-stretch plastic, and very puncture-resistant. They close easily and are Waterproof to 200 feet.
Gifts